Bioaccumulation of Polycyclic Aromatic Hydrocarbons (PAHs) in simping scallops ( Placuna placenta ) from the Waters of Socah and Ujungpangkah, East Java

. The study aimed to investigate the bioaccumulation of Polycyclic Aromatic Hydrocarbons (PAHs) in Placuna placenta scallops from Socah and Ujungpangkah waters in East Java, Indonesia. The research involved sampling from Station 1 at Ujungpangkah and Station 2 at Socah waters. Water, sediment, and Simping scallops were sampled twice, in December 2018 and January 2019. The analysis method used Gas Chromatography-Mass Spectrometry (GC-MS). The analysis results indicated that the total PAHs concentration was higher in Ujungpangkah waters compared to Socah waters. In line with the result of sediment samples, five types of compounds naphthalene, acenaphthene, benzo[ghi]perylene, 2-methylnaphthalene, and 1-methylnaphthalene were found to be more abundant in Ujungpangkah, while Socah waters exhibited the highest concentration of four compounds naphthalene, acenaphthene, 1-methylnaphthalene, and 2-methylnaphthalene. When examining the scallop samples, the highest compound concentrations detected at both locations matched those in the water samples. The Bioconcentration Factor (BCF) value, representing the accumulation of PAHs in Placuna placenta scallops, was higher when obtained from the water than the sediment. In summary, this study revealed varying PAH levels between the two sampling locations, with Ujungpangkah exhibiting higher concentrations than Socah. The results also demonstrated the ability of Placuna placenta scallops to accumulate PAHs from the surrounding water, highlighting their role as bioindicators of environmental contamination.


Introduction1
Indonesian waters boast a remarkable abundance of biodiversity, encompassing a wide range of crustaceans, fish, and mollusks.Bivalvia, commonly known as shellfish, hold significant importance for coastal communities due to their easy availability.Shellfish, such as the Placuna placenta scallop, are highly valued by the public for their protein-rich meat and versatile shells, which can be used for various purposes, ranging from household crafts and wall hangings to high-value jewelry [1].Indonesia is home to various species of clams, but the scalloped clam, Placuna placenta, stands out for its tremendous potential, both in terms of meat utilization and the use of its shell.Catching these bivalves is effortless due to their limited mobility.The scallop, a non-selective filter feeder, also exhibits a sedentary lifestyle, making it an excellent candidate as a sentinel organism based on its characteristics [2], [3].Simping scallop possess a slightly round and flat shape with a tendency toward transparency.Their sizes range from 1.8 to 13.1 cm, with an average size of 3-8 cm within the population.Since scallops lack active mobility and function as non-selective filter feeders, they indirectly serve as bioindicators, providing valuable insights into the condition of their environment [4], [5].Indonesian waters receive significant pollutant inputs, including heavy metals, PAHs compounds, and organic and inorganic waste from human activities such as fishing, transportation, ports, industrial operations, waste discharge from land, and human settlements.These factors collectively impact water quality, affecting the organisms inhabiting the waters [6], [7].
PAHs (Polycyclic Aromatic Hydrocarbons) are a class of hazardous pollutant compounds found in the environment, known for their carcinogenic or mutagenic properties in organisms, including humans [8].These compounds originate from petrogenic (fossil fuel) and pyrogenic (burning of organic materials) sources, possessing chemical properties such as lipophilicity, low solubility, and persistence, making them resistant to environmental degradation [9].Anthropogenic activities primarily contribute to the pollution of PAHs compounds, affecting coastal ecosystems, including mangroves, seagrasses, and vertebrate and invertebrate biota.Chronic exposure to these compounds can lead to mammalian immunological and reproductive disorders, genotoxic effects [6], enzyme response disruptions, and cellular damage [10].
The Placuna placenta scallop, which thrives in specific coastal waters with muddy sediments [11], can be found in the shellfish fishing areas of Ujungpangkah, Gresik, and Socah, Bangkalan [12].Local fishermen often rely on these scallop shells from coastal waters, highlighting the need for knowledge regarding PAHs bioaccumulation in these shells.The objective of this study is to assess the bioaccumulation of PAHs (Polycyclic Aromatic Hydrocarbons) in simping scallops (Placuna placenta) collected from the waters of Socah and Ujungpangkah in East Java, Indonesia.This knowledge will prove valuable in terms of providing information and facilitating efforts to manage scallop resources effectively 2 Materials and methods

Location and time
The research involved collecting samples of water, sediment, and scallop Placuna placenta from two designated stations known as scallop habitats.These stations, namely Station 1 at Ujungpangkah, Gresik and station 2 at Socah, Bangkalan, were selected for the study.Sampling took place at each station on two separate occasions, on 15 December 2018 and 12 January 2019.The research followed a descriptive approach, focusing on data collection to present the actual facts and provide an overview that could be explained by existing theories.The geographic sampling locations can be observed in the map depicted in Figure 1.

Sampling and Analyzing PAHs Compounds
Water samples were collected using a 100 ml Van Don water sampler, whereas sediment samples weighing approximately 500 grams were obtained using an Eckman grab tool, this water and sediment sampling is carried out at 1,2 and 3 sampling point in each location.Scallop samples were manually collected from the Socah station and using a scratching tool at the Ujungpangkah station.A total of 10 scallop individuals measuring 7-10 cm in size were collected.Throughout the transportation process, all samples were carefully preserved at cold temperatures.The analysis of PAHs compounds was conducted using the GC-MS tool, a method that involves the separation of organic compounds through gas chromatography (GC) and the utilization of mass spectrometry (MS) to examine the molecular structure of the analyte.This analysis was carried out at the Chemistry Laboratory of Muhammadiyah University of Malang.

Results and discussion
The results of PAHs analysis from samples of water, sediment, and Placuna placenta scallops are presented in Tables 1, 2, and 3 below.It was found that the water sample from Ujungpangkah contained 18 types of compounds, while the Socah water sample contained 15 types of compounds.The high concentration of PAHs compounds in Ujungpangkah waters is likely due to the presence of numerous fishing boats that generate diesel or fuel waste, as well as the high level of industrial activity in the surrounding area.These compounds can be carried away by currents since the coastal area directly faces the Java Sea, and offshore oil mining activities are nearby.On the other hand, at the location where Placuna placenta scallops were collected in Socah waters, there were only a few fishing boats present (as it is a small boat crossing point to Gresik), resulting in a relatively lower number of PAHs types and a smaller total PAHs value compared to Ujungpangkah waters.Table 1 displays the top five PAHs components, which include naphthalene, acenaphthene, benzo[ghi]perylene, 2-methylnaphthalene, and 1-methylnaphthalene.
Fishing boats that use diesel engines and fuel are the most probable sources of PAHs pollution in the water, as supported by reference [8].It has been shown that PAHs in unburned diesel fuel are the main contributors to the particulate phase of PAHs in diesel engine exhaust.The elevated level of naphthalene in this water sample can be attributed to the combustion process (Pyrosynthesis) of lubricating oils containing two and three-ring PAHs, contributing to higher emissions of five-ring PAHs.Burning residual naphthalenes has been identified as the source of 24% of naphthalene in diesel exhaust emissions and converting 2-methylnaphthalene fuel to naphthalene in the combustion chamber.
Reference [13] reports identifying PAHs types in the coastal waters of Lampung Bay, where the dominant species found were fluoranthene, pyrene, benzo(a)anthracene, and chrysene.These pyrogenic PAHs originate from the incomplete combustion of organic matter and the burning of oils, such as those from fishing boat engines, industrial processes, vehicles, and waste incineration.Phenanthrene and anthracene, PAHs with two to three benzene rings, are sourced from petrogenic (oil) origins, including oil spills from passing ships, leaks from ship fuel or oil, the disposal of used oil, and possibly waste from industrial areas near the sampling location.
According to reference [9], the distribution of PAHs compounds in water, total suspended solids (TSS), and sediments is influenced by water hydrodynamics such as seasonal variations (west and east), tides, and current velocity.Reference [14] examined water samples from Cilincing Jakarta waters and Bintan Island waters, identifying seven types of PAHs: naphthalene, fluorene, anthracene (two benzene rings), fluoranthene, pyrene, benzo(a)pyrene, and chrysene (four benzene rings).The study also investigated the source of PAH pollutants, which could be determined based on the binary ratio of PAHs compounds (as shown in Table 1).
The occurrence of tides along coastal regions significantly influences the distribution pattern of dissolved solids, thereby affecting various ecological processes.In addition to dissolved solids, the tides transport suspended solids, comprising organic and inorganic substances.These suspended solids play a crucial role in facilitating the dispersion of contaminants, including polycyclic aromatic hydrocarbons (PAHs).The analysis of PAHs contaminants in sediments collected from the observation site provides valuable insights, as presented in Table 2.The Ujungpangkah observation site recorded a higher total PAHs value compared to the PAHs levels found in Socah waters.The sediments in both locations contained the same five types of compounds as the water samples in Ujungpangkah: naphthalene, acenaphthene, benzo[ghi]perylene, 2-methylnaphthalene, and 1-methylnaphthalene.However, in Socah waters, four compounds were present in both sediments and water samples: naphthalene, acenaphthene, 1-methylnaphthalene, acenaphthylene, and 2-methylnaphthalene.Additionally, three types of compounds, namely benzo[b]fluoranthene, benzo[k]fluoranthene, and indeno (1,2,3-cd) pyrene, were detected in the sediments but not in the water samples PAHs component.
In a separate study [14], researchers found that the sediments in Bintan Island waters exhibited different characteristics for each type of PAHs.Naphthalene, fluorene, and anthracene, with two or three benzene rings in a linear arrangement, were classified as Low Molecular Weight (LMW) compounds.On the other hand, compounds like fluoranthene, pyrene, benzo(a)anthracene, and chrysene, with four benzene rings arranged angularly and in clusters, fell into the High Molecular Weight (HMW) category.This distinction in the arrangement of benzene rings affects the properties of the PAHs.The presence of certain species exclusively in sediments suggests an accumulation of specific types of PAHs in those locations, potentially due to the topography allowing sediment deposition, proximity to river mouths, or the contours of the waterbed promoting material accumulation, including PAHs pollutants.The collection site in Socah waters is relatively protected from strong currents caused by heavy shipping to Perak Port and the narrowing of the water flow from the Java Sea to the Madura Strait.The accumulation of PAHs in these sediments can significantly impact organisms, particularly benthic biota, including both epifauna and infauna.Scallop meat (Placuna placenta) collected from the observation site was analyzed to assess the bioaccumulation of PAHs.Tables 3 and 4 provide information on the PAHs content in the simping scallops and the bioconcentration of these PAHs.Based on the provided table, it is evident that the PAHs values present in the scallop specimens from Socah and Ujungpangkah waters show remarkable similarity, specifically regarding the presence of naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, and acenaphthylene.This similarity may be attributed to the higher prevalence of these compounds in the water and sediment.Upon evaluating the bioconcentration levels, it was observed that benzo[k]fluoranthene, benzo[ghi]pherylene, and phenanthrene exhibited higher accumulation scores in the Ujungpangkah waters.Conversely, benzo[ghi]pherylene, phenanthrene, and fluorene showed greater accumulation in the sediments.
In the case of the Socah Bangkalan station scallop samples, the highest bioaccumulation of compounds was observed in the water, particularly with pyrene, acenaphthylene, and 2methylnapthalene.Conversely, benzo[k]fluoranthene, benz[a]anthracene, and pyrene demonstrated higher bioaccumulation levels in the sediments.The compounds detected in these sediments closely resemble those found in Bintan Island, as documented in a previous study [14].The bioaccumulation of Polycyclic Aromatic Hydrocarbons (PAHs) in simping scallop (Placuna placenta) has undergone significant development, mainly due to anthropogenic activities such as industrial operations, human settlements, and land-based sources that have the potential to impact water quality.This is evident through various land-based materials, including waste discharge into the sea, such as waste oil, which over ten tributaries can transport.PAHs detected in scallop shells serve as indicators of contaminants and can be utilized for detecting oil spills.The origin of PAHs can be traced back to activities involving oil loading and unloading from ships to tanks and vice versa, as well as fuel discharge from ship engines.Additionally, the adsorption process and water dynamics influence the presence of PAHs in the water [15].
The variance in the occurrence and concentration of PAHs in water and sediment can be attributed to several factors, primarily their distinct physical and chemical properties.PAHs have a short residence time in the water column but can cause chronic effects on organisms, including scallops.Therefore, the concentration of PAHs in the water can elucidate the level of influence of dissolved PAHs on marine organisms.PAHs bioaccumulation in scallop shells can transpire due to various factors, employing diverse mechanisms [16].The concentration of PAHs in sediments holds biological implications for marine organisms associated with sediment.The presence of PAHs in the environment has the potential to be detrimental to organisms, as indicated by the ratio of ERL (low effect range) and ERM (medium effect range) values, which determine the environmental quality of PAHs in sediments [17].
According to [18], the PAHs ratio between compounds reveals that the petrogenic mass pattern is more pronounced in areas closer to land than seaward in offshore sediments.PAHs in water can enter the bodies of organisms, such as fish and shellfish, through various routes, subsequently being rapidly distributed throughout the organism via the circulatory system.PAHs, readily soluble in lipids, can easily permeate cell membranes with a lipid bilayer barrier.The lipophilic nature of PAHs leads to their accumulation in the lipid tissues of organisms.Once inside the body, particularly in the liver, PAHs are metabolized by cytochrome P450, an enzyme assisted by epoxide hydrolase.This metabolism process forms epoxide derivatives, dihydrodiol derivatives, and cation radicals [19].
The metabolism in cytochrome P450 generally produces compounds that have the capacity to bind to DNA, leading to DNA mutations and/or carcinogenic properties.For instance, in the metabolism of benzopyrene, cytochrome P450 generates benzo[a]pyrene 4,5oxide, which binds to DNA [20].According to [21], the classification of total PAHs concentrations includes the following ranges: > 1000 ng g-1 indicates high contamination, 100-1000 ng g-1 indicates moderate contamination, 99-100 ng g-1 indicates low contamination, and < 10 ng g-1 indicates no contamination.
The Sea Water Quality Standard established by the Indonesian government, in accordance with KMNLH 2004 for the benefit of marine organisms, is 0.003 ppm or 3 ppb.The levels of PAHs found in water samples from the Ujungpangkah and Socah waters were below the threshold values, with concentrations measuring 37.08 ppb and 25.91 ppb, respectively.However, in sediment samples, the PAHs levels exceeded those found in the water samples, reaching 8072.7 ppb in the Ujungpangkah sample and 5302.3 ppb in the Socah sample.Similarly, in sediment samples from reference [14], the PAHs levels that could have a negative impact on marine biota were measured at 45 ppm [22].

Conclusion
The PAHs values found in the bodies of scallops collected from the waters of Socah and Ujungpangkah were nearly identical, comprising naphthalene, 1-methylnaphthalene, 2methylnaphthalene, and acenaphthylene.Disparities in the occurrence and concentration of PAHs between different sampling stations in water and sediments can be attributed to the hydrodynamics of the respective bodies of water and the amount of PAHs contaminants being introduced.Bioconcentration of PAHs in shells was observed to be higher in water than in sediments.

Table 1 .
The average value of PAHs (ng/g) content in water samples

Table 2 .
The average results of PAHs (ng/g) analysis on sediment samples

Table 3 .
The average value of PAHs (ng/g) content in scallop shells (Placuna placenta)

Table 4 .
The average value of PAHs Bioconcentration from water and sediment in simping scallop (Placuna placenta)